Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755568Ab0KHVsu (ORCPT ); Mon, 8 Nov 2010 16:48:50 -0500 Received: from www.tglx.de ([62.245.132.106]:37029 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754681Ab0KHVss (ORCPT ); Mon, 8 Nov 2010 16:48:48 -0500 Date: Mon, 8 Nov 2010 22:48:21 +0100 (CET) From: Thomas Gleixner To: Darren Hart cc: Linux Kernel Mailing List , Peter Zijlstra , Ingo Molnar , Eric Dumazet , John Kacur Subject: Re: [PATCH V3] futex: add futex_q static initializer In-Reply-To: <1289252428-18383-1-git-send-email-dvhart@linux.intel.com> Message-ID: References: <1289250770-16533-1-git-send-email-dvhart@linux.intel.com> <1289252428-18383-1-git-send-email-dvhart@linux.intel.com> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2222 Lines: 69 On Mon, 8 Nov 2010, Darren Hart wrote: > The futex_q struct has grown considerably over the last couple years. I > believe it now merits a static initializer to avoid uninitialized data > errors (having spent more time than I care to admit debugging an uninitialized > q.bitset in an experimental new op code). > > With the key initializer built in, several of the FUTEX_KEY_INIT calls can > be removed. > > V2: use a static variable instead of an init macro. > use a C99 initializer and don't rely on variable ordering in the struct. > V3: make futex_q_init const > > Signed-off-by: Darren Hart > Cc: Thomas Gleixner > Cc: Peter Zijlstra > Cc: Ingo Molnar > CC: Eric Dumazet > CC: John Kacur > --- > kernel/futex.c | 25 ++++++++++--------------- > 1 files changed, 10 insertions(+), 15 deletions(-) > > diff --git a/kernel/futex.c b/kernel/futex.c > index fd3fbe1..e6df2de 100644 > --- a/kernel/futex.c > +++ b/kernel/futex.c > @@ -131,6 +131,12 @@ struct futex_q { > u32 bitset; > }; > > +static const struct futex_q futex_q_init = { > + /* list gets initialized in queue_me()*/ > + .key = FUTEX_KEY_INIT, > + .bitset = FUTEX_BITSET_MATCH_ANY > +}; > + > /* > * Hash buckets are shared by all the futex_keys that hash to the same > * location. Each key may have multiple futex_q structures, one for each task > @@ -1751,7 +1757,6 @@ static int futex_wait_setup(u32 __user *uaddr, u32 val, unsigned int flags, > * rare, but normal. > */ > retry: > - q->key = FUTEX_KEY_INIT; You sure about that one in the retry path ? > @@ -1906,11 +1907,7 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags, int detect, > hrtimer_set_expires(&to->timer, *time); > } > > - q.pi_state = NULL; > - q.rt_waiter = NULL; > - q.requeue_pi_key = NULL; > retry: > - q.key = FUTEX_KEY_INIT; Ditto Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/